Solving Can’t Start MariaDB Service on Manjaro GNU/Linux
This Tip Try to Solve “Job for mariadb.service failed because the control process exited with error code” on Manjaro GNU/Linux – Step by step Tutorial.
This issue is usually due to an incomplete MariaDB Setup.

1. Fixing System
Then to Solve mariadb.service failed on Manjaro Linux
Run:sudo mariadb-install-db --user=mysql --basedir=/usr --datadir=/var/lib/mysql